I'd not heard of it before, but the story dates back to 1996:

A huge mysterious door-like structure has recently been discovered in the Hayu Marca mountain region of Southern Peru. Hayu Marca, 35 kilometres from the city of Puno has long been revered by local indians as the "City of the Gods", and has never been fully explored because of the rugged mountain terrain. Although no actual city has ever been discovered, many of the rock formations of the region resemble buildings and artificial structures. The door, or the "Puerta de Hayu Marca" (Gate of the gods/spirits) has been at some time in the distant past carved out of a natural rock face and in all measures exactly seven meters in height by seven meters in width with a smaller alcove in the center at the base, which measures in at just under two meters in height. Source: OneLight.com